[poky] glibc-initial fails to build in Thud with arm926ejs tune

[Richard Purdie]

On Wed, 2019-01-02 at 13:37 -0700, Matthew Stanger wrote:
> I'm getting a build failure under Thud when trying to use the
> following tune in my machine.conf:
> #at91sam9.inc is from meta-atmel - at91sam9263 is ARM target
> require conf/machine/include/at91sam9.inc
> DEFAULTTUNE = "arm926ejs"
> 
> 
> When doing a fresh build 'glibc-initial' config stage fail's with:
> > checking for broken __attribute__((alias()))... yes
> > configure: error: working alias attribute support required
> > WARNING: exit code 1 from a shell command.
> > ERROR: Function failed: do_configure (log file is located at
> /home/matt/renew_thud/build/tmp/work/arm926ejse-poky-linux-
> gnueabi/glibc-initial/2.28-r0/temp/log.do_configure.1177)
> ERROR: Task (/home/matt/renew_thud/build/../oe/poky/meta/recipes-
> core/glibc/glibc-initial_2.28.bb:do_configure)
> failed with exit code '1'
> NOTE: Tasks Summary: Attempted 2173 tasks of which 0 didn't need to
> be
> rerun and 1 failed.
> 
> Summary: 1 task failed:
>   /home/matt/renew_thud/build/../oe/poky/meta/recipes-
> core/glibc/glibc-initial_2.28.bb:do_configure
> 
> Can give follow on config.log's and such as required.
> 
> If I edit 'poky/meta/conf/machine/include/tune-arm926ejs.inc' to
> change the '-mcpu' back to 'mtune'(commit f29d642c) then glibc builds
> fine. GCC tuning is totally outside my expertise so I'm hoping
> someone
> can confirm if '-mcpu' is really desired over '-mtune'? And also if
> this look like a Poky issue or something else?

Are you using thud's default gcc version? I have some memory this issue
may be gcc version specific.

The mcpu verses mtune is open to debate, it depends what your priority
is, feed compatibility across multiple processors or potential micro
optimisation for the processor.

Cheers,

Richard